Impact resistant window

ABSTRACT

An impact resistant window including a frame holding a glass composite structure including first and second glass sheets secured to each other with a middle plastic layer. In a first embodiment, the first glass sheet has a larger perimetrical dimension than the second glass sheet and the second glass sheet is centered on the first sheet to define a peripheral mounting portion. A resilient sealant material fills a space between the peripheral mounting portion of the first glass sheet and the frame structure. In the second embodiment, the two glass sheets may be the same size, but the middle plastic layer extends outwardly from the perimeters of the glass sheets. This extension of the middle plastic layer is used to mechanically connect the laminated pane to a frame.

RELATED APPLICATIONS

This is a continuation-in-part application of U.S. application Ser. No.08/535,537 filed Sep. 28, 1995, now pending.

BACKGROUND OF THE INVENTION

The present invention generally relates to windows and, morespecifically, to an impact resistant window structure especially suitedfor use in houses or buildings located in geographic regions susceptibleto strong weather conditions such as tropical storms and hurricanes.

Impact resistant windows are desirable in many locations and situations.One application is in buildings or houses located in geographic regionswhich are highly susceptible to strong adverse weather conditions, suchas hurricanes, involving extremely high winds. In such conditions, highwinds can hurl large projectiles or debris into windows and the highwinds themselves can create large pressure differentials between theinside and outside of a building. These pressure differentials caneasily blow out or otherwise damage the windows of the house or buildingand cause injury to occupants.

Several local building codes in hurricane zones now require new windowsto conform to strict standards related to the ability of the window towithstand large impacts and large pressure differentials. One standardrequires windows to withstand two strikes by an 8 foot long "two byfour" piece of wood traveling at 34 mph. Then, after these two strikes,the window is subjected to 4,500 positive and 4,500 negative pressurecycles at say 75 psf that simulates the eye of a hurricane passing thebuilding. It appears that adoption of such strict standards will beuniversal in regions such as the southeastern portion of the UnitedStates.

One product which has successfully passed hurricane tests such as theone described above is marketed under the name "SENTRYGLAS". SENTRYGLASis a laminated glass product which may be contained in a conventionalwindow frame structure and includes an outer glass sheet, an outerpolyester film layer and a polyvinyl butyryl layer sandwichedtherebetween to adhere the polyester layer to the glass sheet. Siliconeis used to secure this laminated glass product within the framestructure in a conventional manner. Although this product has passedhurricane tests, it has disadvantages associated with its relativelyhigh cost combined with the fact that the polyester film layer scratchesvery easily and may not be replaced without replacing the entire glasslaminate product.

One attempted solution to this problem involved laminating an additionalglass layer on the opposite side of the polyester film layer to make-thecomposite more similar to conventional laminated glass. This additionalglass layer was of the same length and width dimensions as the firstglass layer. However, when this modified SENTRYGLAS composite issubjected to the hurricane tests such as those mentioned above, theadditional glass layer breaks and cuts or slices through the siliconesealant used to hold the composite in the frame. The glass then vacatesthe window and frame structure and the window therefore fails the test.This is especially true with standard lightweight vinyl or wood windowsused in most residences.

In view of the problems associated with available impact resistantwindow structures, there is a need for an impact resistant window whichcan not only pass the strict hurricane test standards now being imposedbut which is also more aesthetically pleasing and economical than pastimpact resistant windows.

SUMMARY OF THE INVENTION

In accordance with the preferred embodiment of the present invention, awindow structure is provided utilizing a glass laminate structure whichclosely resembles an all glass window and is scratch resistant as wellas highly impact resistant. Generally, the window of the presentinvention includes two outer laminates or sheets which sandwich one ormore laminates or sheets therebetween. Each of the sheets is at leasttranslucent and preferably transparent. In accordance with a firstembodiment of the present invention, one of the outer sheets is reducedin its perimetrical dimension with respect to the other of the outersheets. In the case of a simple four sided window pane shown as thepreferred embodiment, the length and width dimensions of one outer sheetis smaller than the length and width dimensions of the other of theouter sheets.

The larger sized sheet sits a greater distance within the frame of thewindow while the smaller of the two outer sheets preferably only fitspartially within the inside edge of the frame. Preferably, the entireperimeter of the laminated window pane is bounded by a portion whichremains unlaminated by the second, outer sheet. This peripheralunlaminated portion of the window pane is set within a conventionalwindow frame structure and the space formed between the first, largersheet and the inside of the window frame is filled with a sealant orcaulking such as silicone. The middle sheet is preferably a flexibleplastic film layer covering the entire larger sheet and forming anadhesive bond to the silicone.

In the second embodiment, an impact resistant window is providedcomprising a frame structure, a composite sheet structure includingfirst and second rigid translucent sheets and a flexible translucentfilm layer adhered between the first and second rigid translucentsheets. In accordance with this second embodiment, an edge portion ofthe flexible translucent film layer extends outwardly from both thefirst and second rigid translucent sheets and is mechanically affixed tothe frame structure. When impact and pressure tested to simulatehurricane conditions, the mechanical fixation of the flexible film layerto the frame structure has proven to prevent the composite sheetstructure from vacating the frame structure. As in the first embodiment,the first and second rigid translucent sheets are preferably glasssheets. The flexible translucent film layer is preferably adhered to therespective first and second rigid translucent sheets by first and secondlayers of adhesive, which may be the same adhesive used in the firstembodiment. The film layer is preferably a polyester film whichinherently has very little stretch capability.

Although the mechanical fixation of the flexible translucent film layerto the frame structure may be made in various ways, a preferred manneris to affix the edge portion of the film layer between two framecomponents. These two components may be adhesively secured to oneanother, secured by mechanical fasteners such as screws, or securedtogether in any other conventional manner. In the preferred embodiment,the edge portion of the flexible translucent film layer extendstransversely to the composite sheet structure toward one side of theframe structure. This side of the frame structure may be the outside ofthe window and typically has a greater cross-sectional dimension thanthe inside portion of the frame structure. This greater cross-sectionaldimension further strengthens the connection between the composite sheetstructure and the frame structure. A resilient sealing materialpreferably fills spaces between the respective first and second rigidtranslucent sheets and the frame structure. In a further aspect of thesecond embodiment, the edge portion of the film layer preferably extendsaround an entire periphery or perimeter of the first and second rigidtranslucent sheets.

In a further aspect of the invention, an impact resistant window pane isprovided generally comprising a composite sheet structure includingfirst and second rigid translucent sheets each having a perimeter and aflexible translucent film adhered between the first and second rigidtranslucent sheets. The flexible translucent film extends outwardly fromthe perimeter of both the first and second rigid translucent sheets. Thefirst and second rigid translucent sheets are preferably glass sheetsand the flexible translucent film layer again preferably comprises apolyester film. The edge portion of the film preferably extendsoutwardly from the first and second sheets around the entire perimetersof the sheets.

In both embodiments, the two outside laminates are glass sheets whilethe third, inner laminate is a strengthening plastic layer, such as apolyester film. The polyester film may be adhered to both glass sheetsby a compatible adhesive, such as a polyester resin.

With the composite glass laminate structure of the present invention, aglass composite product is formed having both inner and outer glasslayers which therefore give the window a very realistic glassappearance. Also, as both the inside and outside surfaces of the windoware glass surfaces, they are not easily scratched or otherwise marredduring normal use. Finally, in accordance with a main advantage of thisinvention, the glass composite laminate structure of the inventionpasses the hurricane standard tests explained above. In the firstembodiment, as the smaller outside glass sheet does not extend fullyinto the frame structure along with the larger glass sheet, this smallerglass laminate layer does not break away from the larger layer and breakthrough the frame as is the case with prior attempts in this area. Inthe second embodiment, while the two glass sheets may be of the samedimension, the film layer extending outwardly from each glass sheetretains even broken glass within the frame through mechanical fixation.

Additional advantages and objects of the present invention will becomereadily apparent to those of ordinary skill upon review of the followingdetailed description of the preferred embodiment taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a window constructed in accordance withthe preferred embodiment of this invention;

FIG. 2 is a cross-sectional view of the window frame structure and glasslaminate structure in the area surrounding the frame and taken alongline 2--2 of FIG. 1;

FIG. 3 is a plan view of the glass laminate structure of the firstembodiment of the invention without the frame; and

FIG. 4 is a cross-sectional view similar to FIG. 2 but showing analternative glass laminate or composite structure and mechanicalfixation to the window frame structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a simple form of window 10 constructed in accordancewith the present invention. In its most basic form, window 10 comprisesa glass laminate structure or composite 12 fixed within a peripheralframe structure 14. Of course, window 10 may take on many other formsand shapes depending on the needs of the application or the aestheticsdesired, however, the principles of the present invention will remainessentially the same.

FIG. 2 illustrates a cross-sectional view of the frame 14 and theperipheral portion of glass composite 12 which has been secured intoframe 14. Specifically, glass composite 12 has been fixed between anoutside support 16 and an inside support 18 of frame 14. Supports 16, 18extend inwardly from an outer peripheral frame portion 20 which may befixed into a building structure in a conventional manner. Frame 14 maybe a conventional frame and has been schematically shown as such in thedrawings.

Glass laminate structure or composite 12 more specifically includes afirst glass layer or laminate 22 and a second glass layer or laminate 24sandwiching a plastic strengthening layer or third laminate 26therebetween. Glass layer 22 is the outside glass layer and is of alarger overall length and width dimension than inside glass layer 24 asshown in FIG. 3. As also shown in FIG. 3, glass layer 24 issubstantially centered on glass layer 22 to provide mounting portion 22aaround the entire perimeter of laminate structure 12. Glass layer 22 ispreferably about 1-2" larger in both length and width than inside glasslayer 24. Therefore, if glass layer 22 is 24"×24", glass layer 24 may be22"×22" in size. The entire peripheral region 22a of glass layer 22therefore preferably remains "unlaminated" by glass layer 24.

Plastic layer 26 is preferably a polyester film or "PET" layer which isadhesively secured to opposed surfaces of glass layers 22, 24 byrespective adhesive layers 28, 30. Adhesive layers 28, 30 are preferablyformed of a polyester resin which is compatible with both glass and PET.Alternatively, polyvinyl butyryl may be used as the adhesive for layers28 and 30. As shown in FIG. 2, plastic layer 26 and adhesive layer 28preferably extend to the peripheral edge of glass layer 22. Caulking orsealant 32 such as conventional silicone caulking fills the spacebetween peripheral portion 22a of glass layer 22 and frame supportmember 18. The peripheral edge of glass layer 22 also preferably seatsagainst silicone sealant or caulking 33 as shown in FIG. 2. Sealant orcaulking 34 is also applied between frame support 16 and outside glasslayer 22.

As will also be appreciated from FIG. 2, inside glass layer 24 is notreduced in size so much as to expose its peripheral edge 24a outside ofedge 18a of support 18. In other words, inside glass layer 24 is sizedlarge enough to extend just into frame 14 to be hidden from view whenwindow 10 is fully constructed as shown in FIG. 1. Therefore, window 10looks exactly like a conventional window as the unique structure of thepresent invention is hidden from view within frame 14.

During the hurricane tests explained above, in which an 8 foot long twoby four is used to strike window 10 twice at 34 mph and then in whichwindow 10 is subjected to 4,500 positive and 4,500 negative pressurecycles at say 75 psf (simulating hurricane conditions), glass compositeor laminate structure 12 does not break out of frame 14. This isbelieved to be due to the design of the peripheral portions of glasslaminate structure or composite 12. Specifically, peripheral glass layerportion 22a moves against silicone caulking 32 but does not move againstanother glass laminate layer within this space which could break off andslice through caulking 32 and vacate frame 14. In addition, thisembodiment fulfills the objectives of constructing a window which ispleasing in appearance as the areas which are seen between the fourportions of frame 14 are all glass on both the inside and outside of thehouse or building. Finally, the glass composite or laminate product 12is also scratch resistant because of the use of inside and outside glasslayers.

FIG. 4 illustrates the second embodiment of this invention in the formof a cross-sectional view of a window 50, similar to the cross-sectionalview shown in FIG. 2 of the first embodiment. Specifically, window 50includes a composite sheet structure 51 comprising a first rigidtranslucent sheet 52, a second rigid translucent sheet 54 and anintermediate flexible translucent film layer 56. Preferably, this filmlayer 56 is adhered between the two sheets 52, 54 by respective adhesivelayers 58, 60, the thickness of which has been exaggerated for clarity.Adhesive layers 58, 60 are preferably formed of polyester resin as inthe first embodiment. Film layer 56 is preferably a polyester film of aconventional variety as in the first embodiment. One film may beobtained from ICI Films, Inc., Wilmington, Del. under the tradenameMelinex.

Window pane 51 is secured within a frame structure 62, in part byrespective layers of resilient sealing material 64, 66 contained inspaces between window pane 51 and frame structure 62. As in the firstembodiment, this resilient sealing material 64, 66 may be conventionalsilicone caulking. Frame structure 62 may be constructed of aconventional lightweight metal such as aluminum, or may be constructedof vinyl or wood especially if used in typical residential application.Frame structure 62 includes separate frame components 68, 70. Framecomponent 68 is L-shaped in cross section and includes two legs 68a,68b.

In accordance with a main aspect of the second embodiment, an edgeportion 56a of the flexible translucent film layer 56 extends betweenthe two frame components 68, 70. Edge portion 56a extends outwardly fromthe perimeters of both sheets 52, 54. The perimeters of sheets 52, 54are preferably about equal in dimension and the edge portion 56a extendsaround the entire perimeter. Edge portion 56a is mechanically securedbetween frame components 68, 70, for example, by being adhesivelysecured to each component 68, 70. Other conventional manners ofmechanically fixing edge portion 56a to frame structure 62 may equallybe used and include screws or other mechanical fasteners. Thesefasteners may be directed through leg 68b of frame component 68 and intoframe component 70 to secure these two components together.

In a preferred manner of carrying out the second embodiment, edgeportion 56a extends transversely to window pane 51 along leg 68b offrame component 68. Moreover, edge portion 56a is secured within astronger, thicker side of frame structure 62, comprising leg 68b andframe component 70, such that during any impact or any significantpressure differential, the impact or force is directed through windowpane 51, intermediate layer 56 and edge portion 56a to the strongestportion of frame structure 62. This greatly assists in maintaining theintegrity of window 50 during any harsh conditions such as hurricanes.Although this is the preferred manner of securing edge portion 56a, edgeportion 56a may be mechanically fastened within any conventional framestructure in any suitable manner while still obtaining benefits of theinvention, most notably preventing glass shards or pieces from vacatingthe window.

During the hurricane tests explained above, in which an eight foot long2×4 is used to strike window pane 51 twice at 34 mph and in which window50 is subjected to 4,500 positive and 4,500 negative pressure cycles atsay 75 psf (simulating hurricane conditions), the window pane or glasscomposite structure 51 does not vacate frame structure 62. This isbelieved to be due to the design of the peripheral portions of compositestructure 51 in combination with the mechanical fixation of peripheralfilm edge portion 56a within frame structure 62. Specifically, filmlayer 56 holds the entire composite sheet structure 51 together, even ifone or both sheets 52, 54 break, and edge portion 56a holds the entirecomposite sheet structure 51 to window frame structure 62 during theimpact and pressure differential conditions.

In addition, the second embodiment of the invention also fulfills theobjectives of constructing a window which is pleasing in appearance andscratch resistant. Moreover, like the first embodiment, this secondembodiment is also more easily and more inexpensively manufactured thanimpact resistant windows and window panes of the past.

Many modifications may be made to the specific details provided hereinwith respect to windows 10 and 50 including, but not limited to, manyalternative shapes for windows 10 and 50 and alternative designs forframes 14 and 62. Various inner plastic strengthening layers may be usedin the laminate product or composite of the present invention. In thefirst embodiment, these plastic layers may or may not extend to theperiphery of glass layer 22. In the second embodiment, the film layermay or may not extend transversely to the window pane, although certainadvantages such as design compactness and strength are associated withthe transverse orientation. For both embodiments, although variousthicknesses may be used for the glass sheets and inner plastic filmdepending on the application, one preferred composite structure uses1/8" thick glass sheets and polyester film or PET about 3-10 mils thick.

Applicant does not intend to be bound by the specific details providedherein but intends only to be bound by the scope of the appended claims.

What is claimed is:
 1. An impact resistant window comprising:a compositesheet structure including first and second glass sheets havingapproximately equal peripheral dimensions and an intermediate polymericfilm layer, said polymeric film layer being adhered on each side thereofto said first and second glass sheets by respective adhesive layers,said polymeric film layer including an edge portion extendingsubstantially outwardly from all peripheries of said first and secondglass sheets and said adhesive layers; a frame structure havingcomponents encasing outside face portions of each glass sheet andperipheral edge portions of said composite sheet structure; and aresilient sealing material disposed between said frame structure and theoutside face portions of each glass sheet; wherein the edge portion ofsaid polymeric film layer is mechanically affixed between the componentsof said frame structure.
 2. The impact resistant window of claim 1wherein the edge portion of said polymeric film layer extendstransversely to the composite sheet structure toward one side of theframe structure.
 3. The impact resistant window of claim 2 wherein saidone side of the frame structure is of greater cross sectional dimensionthan an opposite side of said frame structure.
 4. The impact resistantwindow of claim 1 wherein the polymeric film layer is formed of apolyester film material.